According to reports, most programs degrade somewhat gracefully on
getting no answer for an MX or a CERT for www.example.com, but many
flip out completely on a NOTIMPL error.

Also, treat a QTYPE_ALL query as just asking for an A record.

The real fix here is to implement proposal 219 or something like it.

Fixes bug 10268; bugfix on 0.2.0.1-alpha.

Based on a patch from "epoch".